Is it obligatory to make up for the day on which water was drunk after being certain of the entry of Fajr, given the difference in Adhan times between mosques and not hearing the Adhan?

If a fasting person doubts the advent of dawn and is not certain of it, and eats and drinks at that time, their fast is valid, and nothing is incumbent upon them, due to Allah's saying: (And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]). So, abstention begins after dawn becomes clear, not merely upon doubting it. This view has been supported by a number of scholars, such as Ibn Abbas, Ata, Al-Awza'i, Al-Shafi'i, and the Hanafis (Ahl ar-Ra'y). If it later becomes clear that they ate after dawn had broken, the preponderant opinion is that there is no make-up fast due upon them.